Sudden cardiac arrest – an abrupt lost of heart function, breathing and consciousness – affects almost 350,000 Americans each year.

The outcomes are even more startling – around 90% of these cases are fatal.

Knowing the risk factors, signs and what to do if you encounter someone going into sudden cardiac arrest could mean the difference between life and death.

What are the causes?

Typically it happens because of a problem with your heart’s electrical system, which can disrupt the heart’s pumping and stop blood flow. It’s not the same as a heart attack, which occurs when blood flow to a part of the heart is physically blocked. But a heart attack can sometimes trigger an electrical disturbance, which leads to sudden cardiac arrest. If not treated immediately, this can be fatal.

“It’s one of the leading causes of death in the U.S.,” said Aneesh Tolat, MD, a cardiac electrophysiologist with Hartford HealthCare’s Heart & Vascular Institute.

> Concerned about an abnormal heartbeat? Connect with a specialist

What are the risk factors?

Dr. Tolat said risk can be genetic, but lifestyle also plays a large role.

These include:

  • A family history of coronary artery disease
  • Smoking
  • High blood pressure
  • High blood cholesterol
  • Obesity
  • Diabetes
  • An inactive lifestyle

What should you do if someone goes into sudden cardiac arrest?

“If you see someone pass out suddenly without any kind of cause or explanation, you do have to worry that it’s sudden cardiac arrest,” Dr. Tolat said. In addition to loss of consciousness, signs include no pulse or breathing.

Immediate CPR is crucial, while another bystander calls 911 and retrieves an automated external defibrillator, if one is available.

Time is of the essence because “you only have about four or five minutes before there is brain damage,” said Dr. Tolat.

Are there warning signs?

A person can experience symptoms in advance, but sudden cardiac arrest often occurs with no warning. Those symptoms include:

  • Chest discomfort
  • Shortness of breath
  • Weakness
  • Fast-beating, fluttering or pounding heart (palpitations)

Dr. Tolat recommends having regular checkups – especially as you get older – to ensure that your heart is healthy.

> Want more health news? Text StartHere to 85209 to sign up for text alerts